U.S. Pat. No. 4,356,838 relates to a guillotine type valve, intended more especially for powdered or granulated products and also for pasty products, such for example as paper pulp. This first invention consisted in forming of a self cleaning valve by adding, on each side of the mobile quillotine plate 2, section members 3 in the form of an elongate rule and more especially longer than the plate, and by bevelling the lower active edge 13 of plate 2 which is applied against an abutment member 4 during closure of the valve.
Now, it has become evident that a few modifications made to this guillotine valve would allow the operation thereof to be considerably improved.
The imperfections noted during construction of the valve according to U.S. Pat. No. 4,356,838 are of several types. First of all, the stellite lining formed on the plate, the abutment member and the slides of the front and rear bodies of the valve only offered a mediocre resistance of these parts to wear. Then, the tightness of the mechanism of the valve with respect to the product was then obtained by the joint effect of a series of different seals, the stacking of which made it difficult to obtain correct clamping of the front and rear bodies of the valve. In particular, two seals were used mounted in two grooves 12 formed on the inner face of each front and rear body of the valve, shoes 7 mounted on springs providing cleaning by wiping the section members 3 as well as an annular stellite lining 19 forming the bearing surface of plate 2 against the internal face of the bodies of the valve.